In many semiconductor devices, diode-like structures are used for different purposes, for instance, to protect an active region of a semiconductor device. In terms of their current-voltage characteristics, diode-like structures typically comprise a forward-biased threshold voltage and a characteristic reverse voltage in a reverse-biased state, above which a leakage current starts to increase significantly.
Typically, a tendency exists to reduce the threshold voltage in the forward-biased state, while the characteristic reverse voltage in the reverse-biased state is to be raised. Naturally, further boundary conditions including process control of the manufacturing process, available space on a substrate of the semiconductor device and other technical restrictions may pose further boundary conditions onto the layout of a semiconductor device and its fabrication process.